Electrode structure for electrical discharge tubes



Feb. 16, 1932. w. F. HENDRY ELECTRODE STRUCTURE FOR ELECTRICAL DISCHARGETUBES Filed Dec. 30. 1927 INYEN'TOR w. 2 H1 Ill Patented Feb. 10, 1932UNITED STATES PATENT OFFICE wILm II. HENDBY, OF OBSDTING, NEW YORK,ASSIGNOB, BY MEBNE ASSIGNKENTQ, TO KANHA'ITAN ELECTRICAL SUPPLY COMPANY,INC., OF JERSEY CITY, NEW JERSEY, A CORPORATION 01 NEW JERSEY ELECTRODESTRUCTURE FOR ELECTRICAL DISCHARGE TUBES Application m December :0, m1.lerlal Io. 243,053.

This invention relates to electrode structures for electrical dischargetubes and per tains more particularly to electrodes of the general typedisclosed in my Patent No. 1,628,045 and copending application SerialNo. 180,788, filed April 4, 1927.

In the above mentioned application is disclosed an improved form ofelectrode structure for an electrical discharge tube of the illuminatingtype. This electrode structure which consists of a point electrodesurrounded by a sleeve of insulating material spaced a slight distancetherefrom, has been found to be very satisfactory in most respects.However, it is necessary carefully to degasify the entire electrodeassembly before putting it into use in a discharge tube. As there isquite a large amount of insulating material in the assembly and thisinsulating material contains a large quantity of absorbed gases,degasification is accomplished only a ter a relatively long treatment.Furthermore, in order to obtain the accurate dimensions desirable forthe parts used in the making of such electrode structures it isnecessary, for best results, to use special insulating material whichcan be reduced to accurate dimensions.

It is an object of my invention in order to avoid the use of largeamounts of insulating material, to provide an improved electrodestructure wherein a specially constructed metal sleeve is used in placeof the insulating sleeves disclosed in the above mentioned applicationand patent. In accordance with my present invention, I hold this sleevein its proper position by insulatingmeans which ma be in the form ofsmall locks of any desirable insulating material, such as porcelain orLavite, moulded or otherwise fashioned to the desired shape. Thisconstruction reduces the amount of insulating ma terial to a minimum andhence reduces the length of time necessary for the degasification of theelectrode structure, while at the same time providin a structure readilyadaptable to mass pro uction in a cheap and manner.

order that the invention me be fully understood I have illustrated in eaccompanying drawings, and described hereinafter, a preferred embodimentthereof.

In the drawings, Fig. 1 illustrates an electrical discharge tube havingpositioned therein an electro e structure constructed in accordance withmy invention.

Fig. 2 illustrates a modified form of electrical discharge tube having asimilar electrode structure therein.

Fig. 3 is a view taken along section lines 33 of Fig. 2.

Fig. 4 shows in perspective one of the block insulators used in theelectrode structure.

Reference numeral 1 indicates an electrode which ma be of any desiredconducting material sucli as aluminum, copper, carbon or the like havinga rod like extension or base 8 and surrounded by a metallic sleeve ofconducting material 2. This metallic sleeve has an extension tube 5which is divided lon itudinally by means of slits 16 into a plurality ofsegments 17 ,each having therein an 0 ening 6 for receiving aninsulating bloc 7. The block 7 may be constructed of any desiredinsulating material such as porcelain, Lavite or similar material,molded or otherwise fashioned tothe desired sha e. The insulating blocksbear a ainst ro -like extension 8 of electrode 1. he blocks are pressedfirmly against the rod 8 by the se cuts 17 of extension tube 5 of sleeve2 which extension is made of sufliciently resilient material to insureproper alignment, through the agency of the insulating plugs, relativeto the rod 8. With this arrangement it is very easy to slide the sleeverelative to the rod and ac tive portion to secure the proper positioningthereof.

Placed around the sleeve 2 for preventing any discharge from flashinback around the lead-in wire of the electro e, and for centering theelectrode structure in the discharge tube, is a flange 4 which has ashoulder 3 for holding the ange in position around the sleeve. In orderto prevent longitudinal displacement of the flange 4 with respect to thesleeve 2, the shoulder 3 of flange 4, and the sleeve 2 are fastenedtogether in some suitable manner, such as by deformation 9. As disclosedin my aforementioned patent the sleeve lon enough to give a goodbearing.

. 13 having an upwa e entlre electrode assembly is positioned within oneend of a discharge tube 10 and is held in its proper position by adeformation 11 in the wall of the tube, with which the flange 4 of thesleeve 2 contacts. The electrode structure is prevented from movement ina backward direction by means of a tubular extension 12 which forms aninwardly.

turned portion'of the envelope of the tube and which surrounds the backend of the rod 8, the inner end of the tube 12 contacting with the endsof insulating blocks 7. The construction'of the insulating blocks isdisclosed more in detail in Fig.4 wherein it willbe noted that theblocks consist of an elongated portion rdly projecting shoulder 14 whichpasses through one of the o nings 6 in the tube 5, the inner face 15 oft e elongated portion 13 being curved to conformto the curvature oftherod 8.

The electrode structure illustrated in' Fig. 2 is exactly the same asthat shown in Fig. 1, it being positioned within a tube 18 in sli t-lydifferent manner than in the tube 10. the tube of this figure theelectrode structure is held in its proper position by a lead-in wire 19which serves to hold the flange 4 of the sleeve 2 against a packing ofglass wool 20 which in turn bears against shoulder 21 of the tube 18. Asset forth in m above mentioned application, the glass woo serves toconduct heat from the electrode structure and thus insure the moreeflicient operation of the tube. While I have illustrated the sleeve 2and flange 4 as bein separate pieces, it will be understood that t eymight likewise be made of a single unitary piece, or the sleeve andflange might be made unitary and fashioned to form a telescope jointwith the extension tube 5. The sleeve 2 might, if desirable, be usedalone without the flange 4. Instead of having three insulating blocks asshown, a different number might be used, and while it is preferable touse blocks having shoulders projectinfg through openings cut in theextension 5 o the sleeve 2, other constructions might be used, forexample, a split cylinder of insulating material might be laced insideof the extension tube 5. I reer to construct the sleeve and flange of seet material, by punching, for example, but in some cases it might befound advantageous,

for structural reasons, to utilize a sleeve of heavy material, die castor machined to the correctdimensions. In such a case, the extension tube5 might be made a separate piece and be telescoped with the sleeve for aportion of its length.

his

from the spirit of the invention as set forth in the following claims.

WhatI claim is:

1. In an electrode structure for an electrical discharge device, anelectrode havin an active portion and a base portion and a s eeve of conucting material surrounding said active portion and se arated a-slightdistance therefrom to provi e a free space, said sleeve being spaced romsaid base rtionb a lurality of radially disposed b ock like ms atingmeans placed between the said base portion and the inside of saidsleeve.

2. In an electrode structure'for an electrical dischar device, anelectrode having an active portion, a base portion, and a metallicsleeve surrounding said active portion at a slight distance therefrom,said sleeve being cut to provide segments, said segments having openingstherein, and insulating means cooperating with said segments andopenings for holding said sleeve in its proper position.

3. In an electrode structure for an electrical discharge device, anelectrode structure comprising an electrode, a metallic sleevesurrounding said electrode at a slight distance therefrom, said sleevehaving cuts at one end dividing said sleeve into segments, andinsulating means positioned between said sleeve and said electrode insuch fashion as to be resilientlly gripped by said segments and to holdsai s eeve in its proper alignment.

4. An electrode structure for an electrical discharge tube comprising anelectrode, and a sleeve having resilient se ents, said sleeve surroundinsaid electr e and be spaced and held in alignment by means 0 insulatorsplaced between. said segments and said electrode.

5. In an electrode structure for an electrical dischar device, anelectrode-having an active portion, a base portion and a metallic sleevesurrounding said active portion at a slight distance therefrom, saidsleeve being cut to provide segments, and insulating means cooperatingwith said segments for holding said sleeve in its proper position.

6. An electrode structure as set forth in claim 5, wherein means isprovided forpreventing dis lacement of the said insulating meansrelative to the said sleeve.

7. In an electrode structure for an electrical discharge device, anelectrode having an active portion and a base portion and a sleeve ofconducting material surrounding said active portion and separated aslight distance therefrom to provide a free space, said materiallyconductive sleeve being electrically cember 1927.

WILLIAM F. IENDRY.

